A variety of security mechanisms exists in the industry for communications between two parties or a limited number of parties. Some of these techniques include such things as public key infrastructure (PKI) techniques that utilize: private and public key pairs; digital certificates; digital signatures; secure sockets layer (SSL) protocols; etc.
Often when the number of parties involved in secure communications increase, the feasibility of traditional two-party or limited-party techniques degrade. For example, if 100 or more parties are using PKI techniques to securely communicate than the time spent by each party to encrypt and decrypt communications can be enormous and can make such an approach impractical.
This type of situation is often presented with television programming or video on demand programming because the potential size of the parties associated with broadcast or multicast content can be very large. Consequently, broadcasting and multicasting service providers have elected to take a different approach.
One such approach includes distributing physical hardware, such as digital subscriber boxes or satellite boxes associated with satellite television program services. Typically, these boxes or other devices (phones, etc.) include a smart card that includes a key used to decrypt and perhaps encrypt communications received or sent. However, if the key of a particular device or box is compromised (stolen) then in order to ensure legitimate use each of the remaining keys on the remaining legitimate devices or boxes have to be changed. This is costly and impractical; so much so that a service provider may elect to permit some unlawful use of its content until a large enough number of violators warrant updating the keys on the legitimate customer boxes or devices.
Therefore, improved techniques for secure broadcasting and multicasting are desirable.